1. Field
An aspect of the present disclosure relates to a virtual machine host server apparatus, and more particularly, to a virtual machine host server apparatus for accelerating booting performance of a virtual machine in an environment in which a virtual machine host server having the virtual machine operated therein and a storage system for storing virtual machine data are connected to each other through a network.
2. Description of the Related Art
According to a conventional art, disk image data of a virtual machine in a virtual machine environment was not stored in a local storage of a virtual machine host server having the virtual machine operated therein but stored in a storage system connected to the virtual machine host server through a network, and input/output of the disk image data was performed using the storage system. Thus, the disk input/output performance according to the operation of the virtual machine converges to the performance of the network and the input/output performance of the storage system. However, according to an input/output workload generated in booting of the virtual machine, most requests for a file having the disk image data stored therein after the booting of the virtual machine are read requests in a sector unit of 512 bytes, and particularly, random reads occupy most of the read requests. Therefore, the booting performance of the virtual machine is degraded due to a network delay time and a disk random read in the storage system.
Accordingly, there was an attempt to detect a virtual machine completely duplicated in a template, load the template in a cache, track data blocks changed in a disk image file of the duplicated virtual machine, and process a read request for unchanged data blocks by reading the unchanged data blocks from the disk image file of the template loaded in the cache, thereby improving the performance of disk input/output generated during operation of the virtual machine. However, the conventional art is limitedly applicable to the completely duplicated virtual machine. Since the entire disk image file of the template is loaded in the cache without considering blocks accessed in the booting of the virtual machine, it is highly likely that data accessed in the booting of the virtual machine will not exist in the cache at a point of time when the data is requested. In addition, when a cache miss occurs, the booting performance of the virtual machine is degraded due to a random read in the sector unit of 512 bytes, which mostly occupies a boot workload.